Lathe tool



Dec. 1.2',` ,195o

LATHE TOOL,v

2 Sheets-.Sheet l Filed. sept. 1o, 1945 E. B; WHIGAM Dec, 12, l195()LATHE Toor.

Sheets-Sheet 2 Filed. Sepft. 10, 1945 Iwf/yme Patented Dec. 12, 1950LATHE TOOL Elgin B. Whigam, United- StatesI Navy, San Francisco, Calif.

Application September 10, 1945, Serial N o. 615,483

(Cl. V82--5-)` (Granted under the act of, M23/20h34. 1.88.13... asy

amended. April 30., 1928;. 310, Q'. Gi 75.7,),

Claims.

This invention relates to lathe. tools; and; more particularly to lathetools of. the type. used in cutting. interior threads or: tor performingother interior cutting; operations in bores.

Lathe tools. Qt the. type referred to. commonly are supported in the.tool post of an engine or muret-lathe and carry a tool bit that may haveone or more cuttingedges, adapted to bear against the; interior surfaceof. a borev in material secured to the chuck: of the lathe so as toont athread therein. upon rotation of the. material thereagainst- Similartools may also be used" to carry other shaped. bits for performing othercutiing operations on the. inside of a bore. In using such tools forcutting threads itis usual-ly necessary to make a plurality ci cuts..often as man37 as eight or tenr in order to; cut a. thread of. thedesired depth Without damaging the material. With tools heretofore used,it has been necessary to adjust the lathe so that. the tool bit. is outof engagement with the thread after the completion of each cnt. beforethe tool can be removed from the bore and' the next cut started. Inaddition there has been no facile means provided for stop-l ping threadsat*- a predetermined longitudinal position in the bore.l

Objects of the presentimention are to provide an improved lathe tool inwhich a too-l bit carried thereby is automatically:disengaged fromthreads bein-g cut in a bore after such threads have been cut. through apredetermined length or distance Within the bore; to provide a lathetool which eliminates the necessity for adjusting the lathe in order toremove the tool from the op.- eration between successive cuts; and toprovide a lathe tool' of the type referred to that is adapt-V able foruse on standard engine or turret'lathes ofl types commonly available.

It is a further object of the invention to provide for carrying out theforegoing objects in a facile, conomical'and eiiicientmanner.

In accomplishing these and other objects of the present invention, 1'rhave provided improved details of structure, the preferred form 'ofwhich is illust-,ratedY in the accompanying. drawings,

wherein:

1 is a. side.V elevational view, partly in sec-v tion, of a lathe toolembodying the features of my invention and showing the relation of theparts as the tool is about to start a threading operation. 1

Fig. z is an end elevational view of the tool shown inv Fig. 1,taken-substantially: on the line II-II of Fig. 1. f

Fig. 3 is. av sectional view of the tcoi Shown in i, takensubstantially' onthefline. lill-PIII of 1g.,

Fig, 4 is. a perspective view of the.I supporting block forl the boringAused in the tool shown Fig'.` 5: iS a: side elevation-a1 view oi thetool shown inl'igf. 11 but showing the relation of the parte as the toolis; cutting a thread and is an- Ploaching the point at' which the.too-1: bit is.k dis-.-

engaged: from; the thread'.y

6 is. a side elevational view orr the tool shown in Fig. but showing,the rotation or the Darts after the tool. has completed. a cut and thetool bit hasr been disengaged. from thread.

Referring morev in detail. tothe drawing-S2 The lathe. tool. ci myinvention comprises' a bodvf t.. Breierablv formed integrally with the ia 2 adapted to. be secured in the tool' post ci a standard engine orturret lathe, not

shown, to support; the tool; during a cutting operation. A longitudinalchannel shaped recess 3 is. preferably formed in the body Ir in the.face opposite the face on vwhich the shank 2- is connected totheb,ody1iig. 2. A longitudinal bore -t is pro..- vided in. the: body t,prefer-ably having its longitudinal axis substantially parallel to therecess 3.. One or more transversehores 5i are also: provided. in thebody l andv extend from the face. on which the. shank 2 is connectedinto the bottom ci. the recess 3, there preferably being two such bores,one of' is located on either side of the Longitudinal bere 4. Thetransverse bores 5 have outer connterbored threaded portions 5.

A block 'l is pivotally connected to the body I within the channel.shaped recess 3 on a pivot stud 8... Referring particularly to Fig:- 4.the block l has a forward lower bearing' Surface 9' that issubstantially' square.. withA respect to the ends of the biock and. arear 10W-er bearing surface l0 that is beveled withv resoect. to theforward bearf inc surface 9. A longitudinal recess il is nrovided. inthe face of the block 1 opposite the bearingfaees 8 and Hi. Therecessll. iS, Slllmunted by clamp, portions t2 and i3, which have. DOI'QS i4therethrough that are-threaded through (me of the portions. l2 or.' I3and are smooth through the other. A latch. or stop member l5 is rigidlyconnected to the rear face. of the.- blocl, L YThe latch or stop memberI5 may be formed .inf tegrauy with the block L but preierablyis in theform of an attached insert, as shown, since it is subject to wear and.is desirably made to. be ref placeable. This latch member l5constitutes part -off a mechanism, hereinafter describwll for' retainingin cutting .position and releasing i121 movement into non-cuttingposition the boring bar assembly of this invention.

Secured within the recess I of the block 1 for longitudinal slidingadjustment is a boring bar I6. A pair of screws I1 are threadedlyengaged through the bores I 4 in the clamp portions I2 and I3 of theblock 1 and are adapted, when tightened, to clamp the boring bar I6 inadjusted position in the recess I The boring bar I6 has an obliquetransverse aperture I3 passing therethrough adjacent the forward endthereof and a longitudinal bore I9 extending from the rearward end ofthe bar into the transverse aperture I8. The rearward end of the bore |9is counterbored and tapped, as indicated at 20, Fig. 1.

The transverse aperture I8 in the boring bar I6 is adapted to receive atool bit 2|. For purposes of illustration, the tool bit 2| is shown as athreading bit of the type having a single cutting edge 22 adapted to cutan interior thread. It is to be understood, however, that such type ofbit is merely exemplary of the tyes of bit that may be employed with thelathe tool. As is well known in the art, an assembly of the typehereinbefore described is generally designated as a boring tool holderof which the actual cutting portion is designated as a cutting bit ortool bit and the extended portion carrying the bit is designated as aboring bar. The bit may be of any desired shape: e. g. similar to aturning tool, in ,e

which case the boring operation results in a smooth-walled cut or e. g.a form cutter, as, for example, a thread cutting tool, in which case theoperation performed by the assembly is entitled boring a thread and theresult is a Workpiece with a thread cut thereon. In either case, theoperation is designated as a boring operation. As is also well known inthe art, the boring bar may be formed integral with the cutting bit ormay be adapted to receive various-separable cutting bits. See MachineTool Operation (Part I) Second edition, by Henry D. Burghardt, publishedby McGraw-Hill, pages 262 et seq. See also Tool Making by Charles B.Cole, published by American Technical Society, 1943, page 104.

VBecause the function performed by my invention is particularlyVvaluable in thread boring operations, the illustrated embodiment showsa boring bar having a threaded bit. Slidably fitted within the bore I9in the boring bar I6 is a rod'23 that extends from the counterboredportion thereof into the transverse aperture I8 and is adapted to bearagainst the tool bit 2| to secure it in adjusted position. A bearingscrew 24 is threadedly engaged in the tapped counterbored portion 2|] ofthe bore I9 and at its-inner end bears against the rearward end of therod 23 to force the rod into tight engagement against the tool bit 2 ISlidably fitted within the longitudinal bore-4 in the body I is aplunger 25 that has a latch head` 26 adjacent its rearward end and acontact .head 21 adjacent its forward end. The latch Ahelicalcompression spring 28 surrounds the plunger 25 between the body I andthe contact head 21. VThe'spring 28 urges the plunger 25 forwardly tothe extent permitted by engagement between the latch head 26 and thebody I. When the forward face ofthe latch head 26 is 691.1-

tact with the body I, the peripheral face thereof contacts the latchmember I5 to retain the elements'of the tool in the relation sho-wn inFig. 1.

A pair of helical compression throw out springs 29 are fitted into thetransverse bores 5 in the body I and are secured therein by screws 3Dthat are threadedly engaged in the counterbored tapped portions 6 of thebores 5. The springs 29 extend from the inner ends of the screws 30 intothe channel shaped recess 3 where they bear against the forward lowerbearing surface 9 of the block 1 and thereby tend to rotate the block 1about the pivot stud 8 in a clockwise direction as viewed in Fig. 1.

An eccentric ring 3| is slidably and rotatably tted around the boringbar I6 rearwardly of the block 1. A set screw 32 is threadedly engagedin the ring 3| and the inner end thereof bears against the outer surfaceof the boring bar I6 to secure the ring in adjusted position withrespect to the boring bar. The outer periphery of the ring 3|constitutes a stop surface which the latch head 26 engages in abuttingrelation to limit the movement of the boring bar assembly into thenon-cutting position shown in solid lines in Fig. 6.

From the foregoing description it is apparent that I have providedmechanism to maintain my boring bar assembly in cutting position and torelease the assembly for spring-pressed movement into non-cuttingposition. This mechanism comprises the latch member I5 and theadjustable stop surface of the eccentric ring 3|, both located on theassembly, and the plunger 25 having the contact head 21 and the latchhead 26 which latter serves as abutment means coacting with the latchmember I5 and the stop surface of ring 3| by direct contact therewith.

Operation The shank 2 is secured in the tool post of a suitable engineor turret lathe. An appropriate tool bit 2| is inserted in the lapertureI8 in the boring bar I6 and secured in adjusted position by tighteningthe screw 24 against the rod 23.

The block 1 is set so that the forward lower bearing surface 9 bearsagainst the bottom of the channel shaped recess 3 in the body I. Thelatch head 26 engages the latch member I5 on the block 1 to retainV theblock and associated elements in this position against the action of thethrow out springs 29, and the tool may be regarded as cocked Fig. 1.

Ilhe screws I1 'are loosened and the boring bar I6 is adjustedlongitudinally in the recess I until the distance between the cuttingedge 22 of the tool bit 2| and the forward face of the contact head 21plus the distance by which the latch head 26 overlaps on the latchmember I5 is equal to the longitudinal distance within the bore that itis desired to have the cutting operation extend. The distance by -whichthe latch head 26 overlaps against the latch member I5 is constant andof a known magnitude for any one tool. The screws I1 are retightened tosecure the boring bar in longitudinal adjusted position.

Fig. 1 shows the tool set in the manner just described and about tostart cutting a thread. The numeral 33 therein designates a piece ofmaterial secured in the chuck of a lathe. The material has a boreinteriorly of which is a partially cut thread 34.

As the feeding of the tool continues, the forward face of the contacthead 21 moves longitudinally with the tool and reaches the point whereit contacts the rearward face of the ma.-

5i: tonal', 33, thisv being; the. condition shown in 'Fig'. 5. Asfeeding: continuesfrom this condition, the plunger" .25 is forcedvrearwardly through the longitudinal bore 4 againsty the Iaction of thespringfZ. Thelatch head is thus pushed out of contact with the latchmember |5- and the tool is"tripped.v

When the tripping occurs, the throw'out springs 29 rotate the block 'lin a. clockwise direction as viewed in Figs. ll and 5y until therearbearing face l0 thereof contacts the bottom of the recess 3cr untilsuch movement is limited by other stop means hereinafter explained. Suchmovement of theblock 1 is transmitted tothe toblfbitl 2| through theboring bar |6 and lifts the cutting edgeA 22 thereof out of the threads34, this being the condition shown in Fig. 6. The -tool is free to beremoved from the bore in the materialy33 without the necessity ofadjusting the lathe.

After the tool has been removed, it mayagaln be cocked to the conditionshown in Fig.l v1 andy theY lathe reset tov make another cut in themateri'al.

The eccentric ring 3| is provided in order to make it possible to varythe arc through which the block 1 rotates when the tool is tripped. Thering 3| may-beslidablv adjusted toward the right as viewed in Fig. 1 toan inoperative position, in which case the block-1 rotates untilthe rearbearing face Il! `thereof contacts the bottom of the recess 3 when thetool is tripped. This is the adjustment normally employed when making yadeep cut in a bore of relatively large diameter, but becomes unsuitableas the depth of cut or the diameter of the bore decreases. The ring 3|may then be moved longitudinally to the position shown in Fig. 1. Withthe ring so positioned, when the tool is tripped, the peripheral face ofthe latch head 26 contacts the peripheral face of the ring 3| to limitthe arc of rotation of the block 1 and associated mechanism. The ring'3| is preferably made eccentric and rotatable in order to increase therange of adiustment, the minimum arc of rotation being obtained when theportion of the ring ot greatest eccentricity is adjacent the latch head26.

While I have shown but one embodiment of my invention, it is susceptibleto modification without departing from the spirit of the invention. I donot wish, therefore, to be limited by the disclosures set forth, butonly by the scope of the appended claims.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

I claim:

1. A lathe tool comprising a body having a longitudinal boretherethrough, means adapted to support the body in the tool post of alathe, a block pivoted to said body for movement between a rst positionand a second position and having a latch member xed thereto, a boringbar secured to said block for longitudinal adjustment thereon, a toolbit carried by said boring bar and being adapted to perform an interiorcutting operation in material secured in the chuck of a lathe in thefirst position of said block and being tree of a cutting so made in theSecond position of said block, spring means in said body urging saidblock to said second position, a plunger slidably supported in saidlongitudinal bore, means on said plunger adapted to contact said body tolimit displacement of said plunger in said bore and :adapted to contact.said latch membermaintain said block in said irst: position against:the action of said springmeans, and meanson plungerA engageable with'material secured in. the chuck .of a lathe to Free said latchmenrber tomove said'V block to said second position.

2. A lathe tool comprising afbcdy'hasring a longitudinal boretherethrough, means. adapted to support the body in the tool post oi aylathe; a lblock pivoted 'to said body for movenieni between a rst'position and a second position and' having a latch member xed thereto; aboring bar secured to said block for longitudinal adjustment thereon; atool 'bitV carried by `said boring bar and being adapted to perform acutting operation on material secured in the chuck of a lathe in thefirst position of said block and' being'- free of a cutting so made'inthe second position of said block; spring means in said body urgingsaidA block to said second position; a plunger slidablyY supported insaid longitudina/l bore; a .contact headdon said plunger, a springcarried on saidy plunger between sai-d Contact head and said-1 forurging sai-:l plunger through saidvbo're, means., on said plungeradapted to abut said latchv member to maintain said blo'ck'in saidl rstposition against the action of said spring means and'to. limitdisplacement of said plunger within said# bore under vthe urging of saidspring; means onsaid plunger engageable withA said materiaiv secured` insaid chuck to move said plungerl to' freesaid latch member wherebysaid-Spring may move said block to said second positionandan ec-'-centric ring mounted on said boring bar and! adapted, upon movement cfsaid abutting means 3. A lathe tool comprising a body; `means adapted tosupport the body in the tool post of a lathe; a boring bar assemblycomprising a block, a boring bar secured for longitudinal adjustment insaid block, and a tool bit carried by said boring bar and adapted toperform a cutting operation on material held in the chuck of a lathe;means pivotally connecting said assembly to said body for movementbetween a rst position in which said bit cuts said material and Vasecond position in which said bit is free of the cut in said materialmade in said first position; spring means urging said assembly to saidsecond position; and mechanism to maintain said assembly in said firstposition and to release seid assembly for movement into said secondposition comprising a plunger supported by said body for slidingmovement relative thereto, a latch member and a stop surface on saidassembly, abutment means on said plunger adapted to engage said body tolimit displacement of said plunger therewithin and to engage said latchmember to maintain said assembly in said rst position against the actionof said spring means and to engage said stop surface to limit themovement of said assembly into said second position, and means on saidplunger engagea-ble with said material in said chuck upon relativemovement oi said tool and said chuck to displace said plunger fromengagement with said latch member; said mechanism being so con- -fstructed as to be adjustable to vary the displacevengageable with saidmaterial supported in said chuck to perform a cutting operation thereonin the 'first position of said boring bar and being 'free of a cuttingso made in the second position of said boring bar; spring means in saidbody urging said boring bar to said second position; a latch memberarranged to pivot as a unit with said boring bar; an eccentric ringmounted on said boring bar having a stop surface thereon; and a plungerslidably supported by said body having a latch head engageable with saidlatch member to maintain said boring bar in said first position againstthe action of said spring means and engageablelwith said stop surface tolimit the movement of said boring bar into said second position andengageable with said body to limit displacement of said plungertherewithin and having `means engageable with the material supported insaid chuck whereby said plunger is moved to disengage said latch member;said eccentric ring being, mounted for adjustment on said boring barwhereby the location on said stop surface engaged by said latch head canbe 'varied to vary the movement of said boring bar from said rstposition to said second position. 5. A lathe tool comprising a body,means adapted to support the body in the tool post of Y 8 a lathe, aboring bar,'means pivotall'y connecting the boring bar to the body'formovement between a. iirst position and a second position, said boringbar being adapted to carry a tool bit engageable with material securedin the chuck of a lathe to perform an interior 'cutting operationtherein in the first position of said boring bar and being free of acutting so made in the second Yposition of said boring bar, spring meansin said body urging said boring bar to said second position, a plungerslidably supported by said body, latch means arranged to pivot as a unitwith said boring bar and engageable with a latch head carried by saidplunger to maintain said boring bar in said first position against theaction of said spring means, said latch head serv ing as a stop to limitdisplacement of said plunger within said body and means on said plungerengageable with material secured in the chuck of a lathe to disengagesaid latch means to move said boring bar to said second position.

ELGIN B. WHIGAM. 7

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS

